Ezekiel was a prophet (holy man) who lived at the same time as the last kings of Judah. God showed Ezekiel events that would happen in the future. God told Ezekiel that Ezekiel must warn the people about these events (Ezekiel 33).
God would punish Judah because its people did not obey God's law. Their enemies would surround Jerusalem, which was Judah's capital city (Ezekiel chapters 4-5). God would leave his temple (the house of God in Jerusalem) - Ezekiel 10. This was because the leaders of Judah served false gods (Ezekiel 8). And the soldiers from Babylon would destroy Jerusalem (Ezekiel 21). God would also punish other evil nations (Ezekiel chapters 25-32).
But God still cared about his people (Ezekiel 37). God would send someone from David's family to be their leader (Ezekiel 37:24-28). We now know that this person was Jesus.
God also showed Ezekiel a picture of a new temple in the future (Ezekiel chapters 40-48). God himself would return to this temple (Ezekiel 43).
The Book of Ezekiel is in the Old Testament section of the Bible.